Analysis of dynamic biomarkers in tumor biopsies is being performed with increasing frequency to help physicians in diagnosis, selecting and assessing treatment, and understanding disease recurrence. Current biopsy techniques were developed to acquire specimens with sufficient numbers of malignant cells for histopathologic diagnosis. However, the tumor content of a biopsy specimen required for pathological analysis is much lower than what is required for molecular profiling of low prevalence mutations or biomarker quantification, which would aid in determining therapeutic options for the patient. This Phase II SBIR will finalize the development of the PSITE ? Photoacoustic System Identifying Tumor Edges ? and will demonstrate the improved diagnostic potential of core needle biopsy (CNB) samples collected using this technology in two large-animal, spontaneous tumor models in vivo. Under the Phase II contract, the contractor will continue progression of the PSITE photoacoustic (PA) technology demonstrated in Phase I, by producing a field-ready prototype that incorporates an optimized device design and performance, and establishment of production documentation and methods towards commercialization of the system. Vertebrate animal studies with significant statistical power will be performed to demonstrate both safety and efficacy of the PSITE, including a fit-for-purpose clinical canine study that will provide data towards determination of a Non-Significant Risk (NSR) classification from the FDA for next-stage human clinical studies.